It's above average for a tacked on multiplayer, sort of in the same vein as Assassin's Creed as being accidentally good.
It's more so because the Mass Effect upgrade system works strangely well for a multiplayer setting. It is challenging, even on Bronze difficulty, but it's clear that some classes are more powerful than others. I am to stubborn to use anything besides the Vanguard class, which is pretty much a death sentence to you and your team if you try to Biotically Bum Rush people.
The guns are a little underpowered, with it taking a full clip from the starter assault rifle to kill the easiest bad guy. It definitely wouldn't hurt to give them a little more power.
Also, when a game requires you to have a team that makes you use team work to properly play, it gets points knocked. I don't like talking to random people, and I really doubt any of my friends are gonna get this game.
But I'm a sucker for customizable armor and color.